The owner of an Upper West Side bar that’s been terrorized by a gang of thieving children said he was threatened by one of the youngsters – as yet another Manhattan business owner came forward Sunday as a victim of the kiddie crime wave. 

Jacob Rabinowitz, owner of the Amsterdam Ale House, was at the bar on West 76th Street Saturday night when he said he spotted one of the children who robbed his patrons back in February panhandling outside his business.

Rabinowitz told The Post he chased the boy away and went on to warn other businesses about the child — which is when the youngster allegedly threatened him.

“He said he was going to beat my ass,” Rabinowitz recalled Sunday. “It was this little kid telling me that.”

When the pub owner warned the child that he would call the police, the boy allegedly replied: “The police can’t arrest me, I’m just a kid.”

The chubby-cheeked crooks – who appear to be no older than 10 – have been targeting businesses in Manhattan and Brooklyn for months, graduating from snatching money in unattended bags to stealing cash from open safes, workers and owners told The Post in an exclusive report on Saturday.

Workers at The Stone Street Tavern in the Financial District on Sunday said they’d also been victimized by the gang of young thieves.

Raul Gomez, 24, a bartender at the tavern, said one of the boys, who he described as a seven- or eight-year-old, stole a waitress’s unattended purse and emptied it out in the bathroom on the afternoon of June 15.

“We’re just telling other people what happened and we found out that a bunch of other places on the street had gotten hit with the same exact manner,” Gomez told The Post.

The owner of Stone Street Tavern said the boy, who caught on camera, appeared to be part of the same group The Post reported had allegedly hit Rabinowitz’s businesses, which also include the Lexington Publick in East Harlem.

The spree began about eight months ago, when two children repeatedly wreaked havoc at Amsterdam Ale House, taking whatever they could snatch from unattended bags.

Things got out of hand in February when the pair grabbed food off a table, pushed a customer and flashed a knife, said manager Whitney Kaufman.

On Aug. 13, a young thief was at it again at Upside on Amsterdam at West 89th Street on the Upper West side, stealing $600 cash from an open safe, cops said.

Last Monday  at 8:30 p.m. at Lexington Publick on Lexington Avenue and East 97th Street, one little thief got about $700 in petty cash from the safe, said the bar’s manager.

It is unclear if the same children are involved in all of the incidents, but several of the Manhattan bar workers said they appear to be.

The Stone Street Tavern owner, who asked to remain anonymous, said the kids seemed at first like normal children selling chocolate and accompanied by their mothers.

The simple panhandling, however, turned sinister when the groups began entering the taverns, with the mothers allegedly allowing their kids to roam free.

“The lads will pretend to go downstairs to the bathroom. That’s where all the offices and the rooms that are for employees only,” the owner noted. “And they go right for the employees’ purses or bags or coats or wallets or whatever they could find.

“They are hitting multiple places on the same day. Like the day they stole the purse at the Stone Street Tavern, they had hit two other places earlier,” he added.

The owner called the situation “really really sad,” and said that even if his employees kick the children out, they always return, sometimes even just 20 minutes later.

Rabinowitz echoed a similar exhaustion over the apparent futility at trying to stop the young bandits, saying that an officer told him Sunday that there was nothing cops could do when he alerted him to the child’s presence outside his pub.

“We small business owners are feeling overwhelmed by this constant barrage of petty theft,” he said. “It seems impossible to keep them away, and it’s frustrating that nothing is being done about it.”

A police spokeswoman said cops were investigating two recent safe thefts, and whether there is a citywide pattern.

Additional reporting by Tina Moore